16 
Hereditary Diseases of Sheep and Pigs. 
Society his conviction of the propriety and importance of 
educating shepherds in such a manner that they may be qualified 
to discharge the momentous duties which frequently devolve 
upon them with promptitude, judgment, and skill. 
II. — Hereditary Diseases ' of Sheep and Pigs. By Finlay 
Dun, Lecturer on Materia Medica and Dietetics at the Edin- 
burgh Veterinary College, and Author of ' Veterinary Medi- 
cines : their Actions and Uses.' 
British agriculturists are daily becoming more and more im- 
pressed with the truth of the familiar saying that " prevention is 
better than cure." They are accordingly employing more skill, 
science, and capital than heretofore, in the management of all the 
domesticated animals, and in the improvement of their sanitary 
condition, by providing them with abundance of suitable food, 
with sheltered pasturages, and with clean, well-ventilated, and 
comfortable abodes, and by protecting them from the ordinary 
causes of disease. But there are other subjects upon which the 
scientific and practical experience of breeders and proprietors of 
stock should be brought to bear, and amongst these we may 
adduce one which has as yet met with too little attention — the 
detection and removal of those hereditary defects and diseases 
by which so much loss and disappointment are occasioned to 
the proprietor of live stock. 
It is the consideration of such diseases among sheep and pigs 
which forms the subject of the present Report ; and in order to 
avoid confusion and unnecessary repetition, we shall discuss it 
under these three heads : — 
I. General considerations regarding hereditary defects and 
diseases. 
II. Hereditary defects and diseases of sheep. 
III. Hereditary defects and diseases of pigs. 
I. There is ample evidence of the hereditary nature of certain 
defects and diseases among the lower animals, as well as among 
men. The progeny of parents affected by various diseases are 
more prone to these diseases, and are affected by them in larger 
proportion, than the progeny of parents in whom such diseases 
have never shown themselves. This is exemplified in consump- 
tion, scrofula, and epilepsy. But the hereditary nature of disease 
is merely a single illustration of a very general and important 
natural law, embodied in the axiom, " like produces like," and 
applying to all the characters and qualities of living beings, 
